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fetchStatURL ()
  • >> fetchStatURL (3) ( FreeBSD man: Библиотечные вызовы )

  • BSD mandoc
     

    NAME

    
    
    fetchMakeURL
    
     
    fetchParseURL
    
     
    fetchFreeURL
    
     
    fetchXGetURL
    
     
    fetchGetURL
    
     
    fetchPutURL
    
     
    fetchStatURL
    
     
    fetchListURL
    
     
    fetchXGet
    
     
    fetchGet
    
     
    fetchPut
    
     
    fetchStat
    
     
    fetchList
    
     
    fetchXGetFile
    
     
    fetchGetFile
    
     
    fetchPutFile
    
     
    fetchStatFile
    
     
    fetchListFile
    
     
    fetchXGetHTTP
    
     
    fetchGetHTTP
    
     
    fetchPutHTTP
    
     
    fetchStatHTTP
    
     
    fetchListHTTP
    
     
    fetchXGetFTP
    
     
    fetchGetFTP
    
     
    fetchPutFTP
    
     
    fetchStatFTP
    
     
    fetchListFTP
    
     - file transfer functions
    
     
    

    LIBRARY

    Lb libfetch
    
     
    

    SYNOPSIS

       #include <sys/param.h>
       #include <stdio.h>
       #include <fetch.h>
    struct url * fetchMakeURL (const char *scheme const char *host int port const char *doc const char *user const char *pwd);
    struct url * fetchParseURL (const char *URL);
    void fetchFreeURL (struct url *u);
    FILE * fetchXGetURL (const char *URL struct url_stat *us const char *flags);
    FILE * fetchGetURL (const char *URL const char *flags);
    FILE * fetchPutURL (const char *URL const char *flags);
    int fetchStatURL (const char *URL struct url_stat *us const char *flags);
    struct url_ent * fetchListURL (const char *URL const char *flags);
    FILE * fetchXGet (struct url *u struct url_stat *us const char *flags);
    FILE * fetchGet (struct url *u const char *flags);
    FILE * fetchPut (struct url *u const char *flags);
    int fetchStat (struct url *u struct url_stat *us const char *flags);
    struct url_ent * fetchList (struct url *u const char *flags);
    FILE * fetchXGetFile (struct url *u struct url_stat *us const char *flags);
    FILE * fetchGetFile (struct url *u const char *flags);
    FILE * fetchPutFile (struct url *u const char *flags);
    int fetchStatFile (struct url *u struct url_stat *us const char *flags);
    struct url_ent * fetchListFile (struct url *u const char *flags);
    FILE * fetchXGetHTTP (struct url *u struct url_stat *us const char *flags);
    FILE * fetchGetHTTP (struct url *u const char *flags);
    FILE * fetchPutHTTP (struct url *u const char *flags);
    int fetchStatHTTP (struct url *u struct url_stat *us const char *flags);
    struct url_ent * fetchListHTTP (struct url *u const char *flags);
    FILE * fetchXGetFTP (struct url *u struct url_stat *us const char *flags);
    FILE * fetchGetFTP (struct url *u const char *flags);
    FILE * fetchPutFTP (struct url *u const char *flags);
    int fetchStatFTP (struct url *u struct url_stat *us const char *flags);
    struct url_ent * fetchListFTP (struct url *u const char *flags);
     

    DESCRIPTION

    These functions implement a high-level library for retrieving and uploading files using Uniform Resource Locators (URLs).

    fetchParseURL ();
    takes a URL in the form of a null-terminated string and splits it into its components function according to the Common Internet Scheme Syntax detailed in RFC1738. A regular expression which produces this syntax is:

        <scheme>:(//(<user>(:<pwd>)?@)?<host>(:<port>)?)?/(<document>)?
    

    If the URL does not seem to begin with a scheme name, the following syntax is assumed:

        ((<user>(:<pwd>)?@)?<host>(:<port>)?)?/(<document>)?
    

    Note that some components of the URL are not necessarily relevant to all URL schemes. For instance, the file scheme only needs the <scheme> and <document> components.

    fetchMakeURL ();
    and fetchParseURL ();
    return a pointer to a Vt url structure, which is defined as follows in In fetch.h :

    #define URL_SCHEMELEN 16
    #define URL_USERLEN 256
    #define URL_PWDLEN 256
    
    struct url {
        char         scheme[URL_SCHEMELEN+1];
        char         user[URL_USERLEN+1];
        char         pwd[URL_PWDLEN+1];
        char         host[MAXHOSTNAMELEN+1];
        int          port;
        char        *doc;
        off_t        offset;
        size_t       length;
    };
    

    The pointer returned by fetchMakeURL ();
    or fetchParseURL ();
    should be freed using fetchFreeURL (.);

    fetchXGetURL (,);
    fetchGetURL (,);
    and fetchPutURL ();
    constitute the recommended interface to the fetch library. They examine the URL passed to them to determine the transfer method, and call the appropriate lower-level functions to perform the actual transfer. fetchXGetURL ();
    also returns the remote document's metadata in the Vt url_stat structure pointed to by the Fa us argument.

    The Fa flags argument is a string of characters which specify transfer options. The meaning of the individual flags is scheme-dependent, and is detailed in the appropriate section below.

    fetchStatURL ();
    attempts to obtain the requested document's metadata and fill in the structure pointed to by its second argument. The Vt url_stat structure is defined as follows in In fetch.h :

    struct url_stat {
        off_t        size;
        time_t       atime;
        time_t       mtime;
    };
    

    If the size could not be obtained from the server, the Fa size field is set to -1. If the modification time could not be obtained from the server, the Fa mtime field is set to the epoch. If the access time could not be obtained from the server, the Fa atime field is set to the modification time.

    fetchListURL ();
    attempts to list the contents of the directory pointed to by the URL provided. If successful, it returns a malloced array of Vt url_ent structures. The Vt url_ent structure is defined as follows in In fetch.h :

    struct url_ent {
        char         name[PATH_MAX];
        struct url_stat stat;
    };
    

    The list is terminated by an entry with an empty name.

    The pointer returned by fetchListURL ();
    should be freed using free (.);

    fetchXGet (,);
    fetchGet (,);
    fetchPut ();
    and fetchStat ();
    are similar to fetchXGetURL (,);
    fetchGetURL (,);
    fetchPutURL ();
    and fetchStatURL (,);
    except that they expect a pre-parsed URL in the form of a pointer to a Vt struct url rather than a string.

    All of the fetchXGetXXX (,);
    fetchGetXXX ();
    and fetchPutXXX ();
    functions return a pointer to a stream which can be used to read or write data from or to the requested document, respectively. Note that although the implementation details of the individual access methods vary, it can generally be assumed that a stream returned by one of the fetchXGetXXX ();
    or fetchGetXXX ();
    functions is read-only, and that a stream returned by one of the fetchPutXXX ();
    functions is write-only.  

    FILE SCHEME

    fetchXGetFile (,);
    fetchGetFile ();
    and fetchPutFile ();
    provide access to documents which are files in a locally mounted file system. Only the <document> component of the URL is used.

    fetchXGetFile ();
    and fetchGetFile ();
    do not accept any flags.

    fetchPutFile ();
    accepts the `a' (append to file) flag. If that flag is specified, the data written to the stream returned by fetchPutFile ();
    will be appended to the previous contents of the file, instead of replacing them.  

    FTP SCHEME

    fetchXGetFTP (,);
    fetchGetFTP ();
    and fetchPutFTP ();
    implement the FTP protocol as described in RFC959.

    If the `p' (passive) flag is specified, a passive (rather than active) connection will be attempted.

    If the `l' (low) flag is specified, data sockets will be allocated in the low (or default) port range instead of the high port range (see ip(4)).

    If the `d' (direct) flag is specified, fetchXGetFTP (,);
    fetchGetFTP ();
    and fetchPutFTP ();
    will use a direct connection even if a proxy server is defined.

    If no user name or password is given, the fetch library will attempt an anonymous login, with user name "anonymous" and password "anonymous@<hostname>".  

    HTTP SCHEME

    The fetchXGetHTTP (,);
    fetchGetHTTP ();
    and fetchPutHTTP ();
    functions implement the HTTP/1.1 protocol. With a little luck, there is even a chance that they comply with RFC2616 and RFC2617.

    If the `d' (direct) flag is specified, fetchXGetHTTP (,);
    fetchGetHTTP ();
    and fetchPutHTTP ();
    will use a direct connection even if a proxy server is defined.

    Since there seems to be no good way of implementing the HTTP PUT method in a manner consistent with the rest of the fetch library, fetchPutHTTP ();
    is currently unimplemented.  

    AUTHENTICATION

    Apart from setting the appropriate environment variables and specifying the user name and password in the URL or the Vt struct url , the calling program has the option of defining an authentication function with the following prototype:

    int myAuthMethod (struct url *u);

    The callback function should fill in the Fa user and Fa pwd fields in the provided Vt struct url and return 0 on success, or any other value to indicate failure.

    To register the authentication callback, simply set fetchAuthMethod to point at it. The callback will be used whenever a site requires authentication and the appropriate environment variables are not set.

    This interface is experimental and may be subject to change.  

    RETURN VALUES

    fetchParseURL ();
    returns a pointer to a Vt struct url containing the individual components of the URL. If it is unable to allocate memory, or the URL is syntactically incorrect, fetchParseURL ();
    returns a NULL pointer.

    The fetchStat ();
    functions return 0 on success and -1 on failure.

    All other functions return a stream pointer which may be used to access the requested document, or NULL if an error occurred.

    The following error codes are defined in In fetch.h :

    Bq Er FETCH_ABORT
    Operation aborted
    Bq Er FETCH_AUTH
    Authentication failed
    Bq Er FETCH_DOWN
    Service unavailable
    Bq Er FETCH_EXISTS
    File exists
    Bq Er FETCH_FULL
    File system full
    Bq Er FETCH_INFO
    Informational response
    Bq Er FETCH_MEMORY
    Insufficient memory
    Bq Er FETCH_MOVED
    File has moved
    Bq Er FETCH_NETWORK
    Network error
    Bq Er FETCH_OK
    No error
    Bq Er FETCH_PROTO
    Protocol error
    Bq Er FETCH_RESOLV
    Resolver error
    Bq Er FETCH_SERVER
    Server error
    Bq Er FETCH_TEMP
    Temporary error
    Bq Er FETCH_TIMEOUT
    Operation timed out
    Bq Er FETCH_UNAVAIL
    File is not available
    Bq Er FETCH_UNKNOWN
    Unknown error
    Bq Er FETCH_URL
    Invalid URL

    The accompanying error message includes a protocol-specific error code and message, e.g. "File is not available (404 Not Found)"  

    ENVIRONMENT

    FETCH_BIND_ADDRESS
    Specifies a hostname or IP address to which sockets used for outgoing connections will be bound.
    FTP_LOGIN
    Default FTP login if none was provided in the URL.
    FTP_PASSIVE_MODE
    If set to anything but `no' , forces the FTP code to use passive mode.
    FTP_PASSWORD
    Default FTP password if the remote server requests one and none was provided in the URL.
    FTP_PROXY
    URL of the proxy to use for FTP requests. The document part is ignored. FTP and HTTP proxies are supported; if no scheme is specified, FTP is assumed. If the proxy is an FTP proxy, libfetch will send `user@host' as user name to the proxy, where `user' is the real user name, and `host' is the name of the FTP server.

    If this variable is set to an empty string, no proxy will be used for FTP requests, even if the HTTP_PROXY variable is set.

    ftp_proxy
    Same as FTP_PROXY for compatibility.
    HTTP_AUTH
    Specifies HTTP authorization parameters as a colon-separated list of items. The first and second item are the authorization scheme and realm respectively; further items are scheme-dependent. Currently, only basic authorization is supported.

    Basic authorization requires two parameters: the user name and password, in that order.

    This variable is only used if the server requires authorization and no user name or password was specified in the URL.

    HTTP_PROXY
    URL of the proxy to use for HTTP requests. The document part is ignored. Only HTTP proxies are supported for HTTP requests. If no port number is specified, the default is 3128.

    Note that this proxy will also be used for FTP documents, unless the FTP_PROXY variable is set.

    http_proxy
    Same as HTTP_PROXY for compatibility.
    HTTP_PROXY_AUTH
    Specifies authorization parameters for the HTTP proxy in the same format as the HTTP_AUTH variable.

    This variable is used if and only if connected to an HTTP proxy, and is ignored if a user and/or a password were specified in the proxy URL.

    HTTP_REFERER
    Specifies the referrer URL to use for HTTP requests. If set to ``auto'' the document URL will be used as referrer URL.
    HTTP_USER_AGENT
    Specifies the User-Agent string to use for HTTP requests. This can be useful when working with HTTP origin or proxy servers that differentiate between user agents.
    NETRC
    Specifies a file to use instead of ~/.netrc to look up login names and passwords for FTP sites. See ftp(1) for a description of the file format. This feature is experimental.
    NO_PROXY
    Either a single asterisk, which disables the use of proxies altogether, or a comma- or whitespace-separated list of hosts for which proxies should not be used.
    no_proxy
    Same as NO_PROXY for compatibility.

     

    EXAMPLES

    To access a proxy server on proxy.example.com port 8080, set the HTTP_PROXY environment variable in a manner similar to this:

    HTTP_PROXY=http://proxy.example.com:8080

    If the proxy server requires authentication, there are two options available for passing the authentication data. The first method is by using the proxy URL:

    HTTP_PROXY=http://<user>:<pwd>@proxy.example.com:8080

    The second method is by using the HTTP_PROXY_AUTH environment variable:

    HTTP_PROXY=http://proxy.example.com:8080
    HTTP_PROXY_AUTH=basic:*:<user>:<pwd>
    

    To disable the use of a proxy for an HTTP server running on the local host, define NO_PROXY as follows:

    NO_PROXY=localhost,127.0.0.1
    
     

    SEE ALSO

    fetch(1), ftpio(3), ip(4)
    J. Postel J. K. Reynolds October 1985 File Transfer Protocol RFC959
    P. Deutsch A. Emtage A. Marine. May 1994 How to Use Anonymous FTP RFC1635
    T. Berners-Lee L. Masinter M. McCahill December 1994 Uniform Resource Locators (URL) RFC1738
    R. Fielding J. Gettys J. Mogul H. Frystyk L. Masinter P. Leach T. Berners-Lee January 1999 Hypertext Transfer Protocol -- HTTP/1.1 RFC2616
    J. Franks P. Hallam-Baker J. Hostetler S. Lawrence P. Leach A. Luotonen L. Stewart June 1999 HTTP Authentication: Basic and Digest Access Authentication RFC2617
     

    HISTORY

    The fetch library first appeared in Fx 3.0 .  

    AUTHORS

    An -nosplit The fetch library was mostly written by An Dag-Erling Sm/orgrav Aq des@FreeBSD.org with numerous suggestions from An Jordan K. Hubbard Aq jkh@FreeBSD.org , An Eugene Skepner Aq eu@qub.com and other Fx developers. It replaces the older ftpio library written by An Poul-Henning Kamp Aq phk@FreeBSD.org and An Jordan K. Hubbard Aq jkh@FreeBSD.org .

    This manual page was written by An Dag-Erling Sm/orgrav Aq des@FreeBSD.org .  

    BUGS

    Some parts of the library are not yet implemented. The most notable examples of this are fetchPutHTTP (,);
    fetchListHTTP (,);
    fetchListFTP ();
    and FTP proxy support.

    There is no way to select a proxy at run-time other than setting the HTTP_PROXY or FTP_PROXY environment variables as appropriate.

    libfetch does not understand or obey 305 (Use Proxy) replies.

    Error numbers are unique only within a certain context; the error codes used for FTP and HTTP overlap, as do those used for resolver and system errors. For instance, error code 202 means "Command not implemented, superfluous at this site" in an FTP context and "Accepted" in an HTTP context.

    fetchStatFTP ();
    does not check that the result of an MDTM command is a valid date.

    The man page is incomplete, poorly written and produces badly formatted text.

    The error reporting mechanism is unsatisfactory.

    Some parts of the code are not fully reentrant.


     

    Index

    NAME
    LIBRARY
    SYNOPSIS
    DESCRIPTION
    FILE SCHEME
    FTP SCHEME
    HTTP SCHEME
    AUTHENTICATION
    RETURN VALUES
    ENVIRONMENT
    EXAMPLES
    SEE ALSO
    HISTORY
    AUTHORS
    BUGS


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